With the freezing of the Long Term Evolution (LTE) project of the Universal Mobile Telecommunications System (UMTS) technique initiated by the 3GPP, the 3GPP organizations has begun studying the fourth generation (4G) mobile telecommunications system, e.g., the LTE-Advanced (LTE-A). In order to meet the requirement of high data rate of the 4G system (1 Gbps for downlink and 500 Mbps for uplink) required by the ITU, the 3GPP proposes a carrier aggregation technique in the LTE-A to support a bandwidth capable of providing the high data rate. The carrier aggregation technique can aggregate a plurality of carriers of different frequency ranges to form a maximum bandwidth of 100 M, so that the User Equipment (UE, also referred to as mobile terminal, mobile station, etc.) of the LTE-A can receive and/or transmit data on the plurality of carriers, thereby the bandwidth for transmitting or receiving data is more than 20 M. In the carrier aggregation technique, each aggregated carrier is called as a Component Carrier (CC).
In the carrier aggregation system, the base station (Evolved NodeB, eNB) end is provided with a plurality of CCs, and the UE also supports transmitting and receiving data on the plurality of CCs simultaneously. Currently, the study of the carrier aggregation technique by the 3GPP is in a slow progress, and particularly in the study of the high layer technique, only some concepts and basic flows are defined, while the technical details are not studied. Since the carrier aggregation technique is mainly used to provide a support of higher rate to the UE, there is no effect on the UE in an idle state. On this basis, it is agreed in the industry that for the UE in an idle state, only one of the CCs is available, and the service connection is set up through that CC. For the convenience of description, such CC is referred to as a primary carrier in the present invention, while other CCs in the same carrier aggregation system are referred to as additional carriers.
In the carrier aggregation technique, the signaling and control channel supporting multi-carrier transmission shall be re-designed in the physical layer, and a high layer protocol shall also be designed for management of the multiple carriers, including configuration of a carrier set of the UE, and addition, removal, etc. of carriers in the carrier set. Currently, the following two basic solutions are being discussed for the carrier management.
Solution 1: a solution based on one step, i.e., there is only a carrier configuration process. Specifically, one or more additional carriers are configured for the UE through a high layer signaling. After the configuration, the UE can receive control information and data on the configured carrier(s).
Solution 2: a solution based on two steps, i.e., a configuration process and an activation process. Specifically, firstly one or more additional carriers are configured for the UE through a high layer signaling. After the configuration, the UE cannot immediately receive control information or data on the configured carrier(s). Instead, when the downlink traffic volume of the UE is increased, the base station activates the configured one or more carriers through further signaling. Only after the carrier(s) being activated can the UE receive control information and data thereon. When the downlink traffic volume of the UE is decreased, the base station can deactivate the one or more carriers through a high layer signaling.
Compared with Solution 1, Solution 2 requires additional activation and deactivation signaling. In Solution 2, the additional carrier(s) can be activated and deactivated upon the traffic volume demand from the UE, so as to better save the UE power. But the above two solutions are still being discussed, and there is no concrete implementation process. Therefore, a concrete implementation solution for performing a carrier management shall be proposed for the carrier aggregation system.
To be noted, the above conventional techniques are just illustrated for the convenience of clearly and completely describing the technical solution of the present invention, and facilitating the appreciation by a person skilled in the art. It shall not be deemed that those solutions are known to a person skilled in the art just because they are illustrated in the Background of the Invention.
Some relevant literatures cited in the present invention are listed as follows, and incorporated herein by reference, as if they were detailedly described in the Specification.
1. US patent application with a publication No. US 20090268831A1;
2. US patent application with a publication No. US 20090257517A1;
3. US patent application with a publication No. US 20090219910A1;
4. International patent application with an international publication No. WO 2009120123A1;
5. Chinese patent application with a publication No. CN101465720.